1. Field of the Invention
The present invention relates to an adjustable dumbbell, and more particularly to an adjustable dumbbell including an improved structure for allowing the weight members to be easily and adjustably attached to or disengaged from the weight carrier or handle and for allowing the adjustable dumbbell to be easily operated by the users.
2. Description of the Prior Art
Typical dumbbells comprise a handle to be grasped or held by the user, and a number of weight plates to be attached onto the ends of the handle for weight lifting or exercising purposes, or for exercising or training the upper muscle groups or the lower muscle groups of the user.
For example, U.S. Pat. No. 5,839,997 to Roth et al. discloses a typical adjustable dumbbell comprising a series of plates in stacked relationship, a handle having a shaft passing through the weight plates, and a sleeve and a plate engaged onto the shaft and the weight plates for selectively or adjustably attaching the weight plates to the shaft.
However, the sleeve and the plate may not be easily or quickly assembled onto the shaft and into the weight plates such that the typical adjustable dumbbell may not be easily or quickly assembled or manufactured.
U.S. Pat. No. 5,879,274 to Mattox discloses another typical adjustable dumbbell comprising a series of weighted plates to be attached onto the ends of the handle, and a number of receptacles and spring-biased shafts are required to be attached onto the ends of the handle for mounting or securing the weighted plates on the ends of the handle.
However, the receptacles and the spring-biased shafts may not be easily or quickly assembled onto the handle such that the typical adjustable dumbbell may not be easily or quickly assembled or manufactured.
U.S. Pat. No. 6,656,093 to Chen discloses a further typical dumbbell comprising a handle which can be grasped or held by the user, a number of weight plates to be attached onto the ends of the handle for exercising or training the arms or the feet of the user, and a latch attached onto the end of the handle and/or the weighted plates for selectively or adjustably mounting or securing the weighted plates on the ends of the handle.
However, the latch may not be easily or quickly assembled onto the handle or the weighted plates such that the typical adjustable dumbbell may not be easily or quickly assembled or manufactured.
U.S. Pat. No. 6,719,674 to Krull, and U.S. Pat. No. 6,733,424 to Krull disclose the further typical adjustable dumbbells each comprising a series of weighted plates to be attached onto the ends of the handle, and a number of weight selectors or selector rods should be attached onto the ends of the handle and/or the weighted plates for selectively or adjustably mounting or securing the weighted plates on the ends of the handle.
However, the weight selectors or selector rods may not be easily or quickly assembled onto the handle or the weighted plates such that the typical adjustable dumbbell may not be easily or quickly assembled or manufactured.
U.S. Pat. No. 7,137,931 to Liu, U.S. Pat. No. 7,172,536 to Liu, and U.S. Pat. No. 7,223,214 to Chen disclose the other typical adjustable dumbbells each comprising a series of weighted plates to be attached onto the ends of the handle, and a number of latching members or a complicated latch device should be attached onto the ends of the handle and/or the weighted plates for selectively or adjustably mounting or securing the weighted plates on the ends of the handle.
However, the latching members or the complicated latch device may not be easily or quickly assembled onto the handle or the weighted plates such that the typical adjustable dumbbell may not be easily or quickly assembled or manufactured.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional adjustable dumbbells.